A visitor walks on a giant chalk artwork called “Wasting Time” at the Chalk Urban Arts Festival in Sydney on October 25, 2014. The picture is the biggest 3-D artwork created in Australia by two artists, Leon Keer from Holland and Jenny McCracken from Australia. (Photo by Peter Parks/AFP Photo)

Labourers walk near trucks loaded with logs, which are trapped on a muddy road, near an unreserved forest in the village of Igbatoro, southwest Nigeria, August 28, 2014. Wood, a form of biomass, is the sole source of energy for hundreds of millions of Africans who lack access to modern sources of power, and logging, both legal and illegal, remains a lucrative business that has contributed to the rapid shrinking of Africa's rainforests and woodlands. (Photo by Akintunde Akinleye/Reuters)

A picture rotated 180 degrees shows visitors walking inside an “Upside-down House” attraction at the VVTs the All-Russia Exhibition Center in Moscow, on January 14, 2014. The attraction to experience a new perspective of a house standing upside down was opened first time in Russia, the show organisers said. (Photo by Alexander Nemenov/AFP Photo)

A shorn alpaca walks in a grass field at Alpaca-Land farm in Unken in the Austrian province of Salzburg, Sunday July, 6, 2014. The annual shearing makes the animals more comfortable for the summer months. (Photo by Kerstin Joensson/AP Photo)

Walkers cross the river Waalbrug during the first day of the 98th annual four-days walking event, the “Vierdaagse” in Nijmegen, Netherlands, July 15, 2014. The “Nijmeegse Vierdaagse” is an annual public four-day field march which is held since 1909 in the third week of July. (Photo by Erik van 't Wout/EPA)

The Revere Hotel in Boston, Ma. celebrated its grand opening on April 18 with a vertical fashion show. The Boston Rock Gym provided the models who rappelled down the exterior of the 24-story hotel wearing outfits created by the students from the Massachusetts College of Arts and Design and by Ted Baker London.

Photo: A model walks down the side of Revere Hotel in Boston during a vertical fashion show for the Massachusetts College of Art and Design on April 18, 2012. (Photo by Dominick Reuter/EPA/Lauren Fish/Lauren Frohne/Globe photo)

A man in a mock space suit experiences walking in space at “Mars Base 1 Camp” on May 15, 2023 in Jinchang, Gansu Province of China. The simulated Mars base allows visitors to immerse themselves in the Mars experience. (Photo by Li Yalong/China News Service/VCG via Getty Images)